Modems Matter From 300 Baud to 56K The modem is a gatekeeper, boundary-walker, border-crosser, turnstile-hopper, time traveler, and translator. In the early days of the net, the modem was a technology of distinction. Those who knew the modem's song were identified with it-- they were modemers, inhabitants of a modem world, agents of a modem era. Properly cared for and initialized, the modem's incan- tation revealed a new communicative field enveloping the mundane. Operating at the brittle edge of rationality, the modem was a charged device, transforming data into song using a vibrating crystal to keep time. The term "modem" is a contraction of its two core functions: modulation and demodulation. In practical terms, a modem transmits a stream of digital information (e.g., 1001110100101) over a plain old telephone line by first generating an audible "carrier" signal and then periodically altering, or "modulating," that signal to represent a sequence of 1s and 0s. The receiving modem recovers the 1s and 0s by listening for changes in the carrier signal. The precise pitches and tempo of the modem's song are defined by a "protocol." Communication protocols are produced by committees of engineers aiming to efficiently push the maximum amount of information through a noisy medium. While modems typically include an error correction mechanism, they don't really care about the meaning of the data they transmit. A rogue messenger, the modem is a technology of communication rather than computation. In the late 1970s, dial-up modems brought together the long tradition of amateur telecommu- nications and the emerging technical culture of microcomputing. With the introduction of the modem, the microcomputer was transformed into a medium for communication and the telephone network was remade into a space for experimentation and play. Life online began with the sound of a modem. In 1962, AT&T began to advertise a new device called the Data Set 103A. The Data Set, also known as the "DATA Phone," was marketed to large organizations as part of a long-distance data communications package. The Data Set weighed 15 lbs. and shipped with industrial mounting brackets. An instructional video showed a woman sitting at a control console, surrounded by data processing equipment. After placing a phone call and exchanging pleas- antries with someone on the other end, she asks, "Can my machine talk to your machine?" and proceeds to feed a stack of punched cards into the machine. As each card passes through the reader, a burst of high-pitched, staccato music rang out into the room; our diva's debut. FREQUENCY (Hz) STATION SIGNAL MODE TRANSMITTED DATA SET DATA SET 103A1 103A2 f mark (f m) 1070 1270 Originating 1 1 f1 space (f1s) 1270 1070 f mark (f m) 2025 2225 Answering 2 2 2225 2025 f2 space (f2s) The Data Set protocol, or Bell 103A, defined four frequencies for the transmission of "marks" (1) and "spaces" (0) between "originating" and an "answering" stations. The protocol also pegged the rate of digital exchange to a steady 300 bits (or about 40 alphanumeric characters) per second. Fifty years later, these same four frequencies continue to provide a fallback communi- cation protocol for the global information infrastructure. Initially, AT&T exercised total control over the Bell System and only their modems could be attached to the network. In 1968, the FCC decided that AT&T could no longer prevent users from connecting their own devices, provided that they did no harm to the system. While this decision made modems strictly legal, many American homes lacked standard telephone jacks well into the late-1970s. Even if a modem were available, they would have had nowhere to plug it in! To circumvent the lack of a standard wall jack, early modems adopted an "acoustic coupler" design. Acoustic couplers featured a speaker and microphone carefully positioned to match the handset of a West- ern Electric Model 500 telephone. The availability of wall jacks was so uncertain that Radio Shack contin- ued to sell acoustic couplers until 1992. In March 1976, the cover of Popular Electronics maga- zine boasted an "exclusive" modem project by Lee Felsenstein, a radical engineer known for his early experiments with microcomputers and online communities. The "Pennywhistle" busted open the closed world of the microcomputer, enabling hobby- ists to more easily move data in and out of their machines-- no simple task in the days before afford- able floppy drives. In fact, the primary use for the Pennywhistle was not telecommunications but data storage. In addition to its acoustic coupler, the Penny- whistle included an audio jack to interface with yet another new medium: the audio cassette recorder. Like the Data Set, the Pennywhistle modem was a hands-on device that could not be operated autono- mously. A human being still needed to pick up the telephone handset, dial a number, and listen for a carrier tone on the other end of the call. The Hayes Smartmodem, with its "stackable" alumi- ly prized among phone phreakers who took advan- num case, blinking red LEDs, and fairy tale origin story, tage of the programmable dialer, tone generator, and is an icon of 1980s telecomputing. In 1977, at a dining handset interface for spelunking the Bell System. room table in an Atlanta suburb, two friends endeav- ored to design an affordable modem for the hobbyist In the modem world, transmission speed was about community. Their first product was a pre-assembled more than user patience or convenience. Long-dis- expansion card for the popular S-100 "Altair" platform. tance dialing was billed according to call duration so it The owner's manual suggested a variety of social was in a modemer's best interest to get off the line as applications for the modem such as building a quickly as possible. Likewise, most bulletin board database for your local computer club, running multi- systems were "one-liners" that could accommodate player games, and telecommuting to save on just a single user at a time. Therefore, it was also in the gasoline. community's best interest to keep each connection as time-brief and data-rich as possible. In 1981, Hayes released the Smartmodem, a sharp-looking device designed to fit neatly beneath a But, a technological chasm yawned between 2400 and Model 500 telephone. By this time, microcomputing 9600 baud. The International Telecommunication had grown beyond the hardcore hobbyist clique Union's standard for 9600 baud transmission, V.32, thanks to pre-built machines like the Radio Shack required manufacturers to implementation a tricky TRS-80 and Commodore PET. Whereas most modems echo cancellation algorithm, the cost of which would were vendor-specific, the external Smartmodem have driven up the price of their modems. At connected to any PC with an RS-232 serial port. $700-1200, high-speed modems already exceeded the Further, the Smartmodem came with its own micro- typical middle-class hobby budget. processor, a Zilog Z8 chip that could be programmed to automatically answer the phone, dial numbers, The USRobotics Courier HST was one of a handful of change modes, and hang up. Finally, the Smartmod- new modems to skirt the ITU standard by introducing em included an internal loudspeaker to fill your room a proprietary protocol. Competitive with peer devices with that memorable modem song. from Telebit and Hayes, USRobotics was unique in its enthusiastic embrace of the BBS scene. For years, they By the mid 1980s, the "Hayes command set" had offered BBS sysops a deep discount in exchange for an become a de facto standard and nearly all consumer electronic shout-out. Thanks to the sysop program, modems were advertised as "Hayes-compatible." the Courier HST became known as an affordable While many modem makers were content to produce high-speed workhorse (with positive externalities for clones of the Smartmodem, others began to experi- its maker!) ment with the notion of a "smart" modem, crafting special-purpose companion devices rather than mere Like the Apple-CAT II, the USRobotics Courier HST was peripherals. a hit among the warez underground (which now involved massive hierarchical organizations) but it also In 1981, Novation Inc. released the Apple-CAT II, a facilitated the growth of translocal messaging complex piece of telecom hardware billed as "more networks such as FidoNet, RelayNet, and WWIVnet. than just a modem...a personal communication For both file-traders and message nets, HST connec- system." The Apple-CAT II shipped with a variety of tions enabled the global circulation of data by reduc- oddball accessories including a pair of plastic hooks ing the burden on each transnational link. for hanging a telephone handset off the side of the Apple II chassis. Novation packed the device's Meanwhile, amateur radio operators (or "hams") were firmware with a grip of uncommon features including finding uses for modems in their wireless hobby as a half-duplex 1200 baud high-speed mode based on well. In 1978, hams in Canada began to exchange data the Bell 202 standard, a communications protocol so over the air using second-hand Bell-compatible uncommon that it was practically exclusive. The modems with homebuilt interfaces or "terminal node four-fold speed boost was catnip to data-hungry controllers" (TNC). Doug Lockhart (VE7APU), founder software collectors and sysops were keen to advertise of the Vancouver Amateur Digital Communications high speed CAT lines. Beyond file traders, the Group (VADCG), designed the first widely used TNC Apple-CAT offered compatibility for telecommunica- kit, which came to be known as the "VADCG TNC." tions devices for the deaf (TDD) and became especial- Soon, "packet radio" spread to the U.S.